Even though the cost of setting up and operating an automatic press just for pre-production sample seems prohibitive, generating the sample on the same press you plan to use to handle the entire job run offers a number of advantages. I have mentioned in the past that the inherent variables that the human hand brings to the table prevent the manual printing process from matching the repeatability of an automatic. This fact holds truer than ever when it comes to producing approval samples.

Consistency, intensity, and other variables

Perhaps the greatest justification for using automatics in the production of approval samples is in the squeegee stroke. Regardless of the care taken or experience acquired in manual sample production, the human hand cannot emulate the consistency of the automatic press’s control over the squeegee’s speed, pressure, and angle. The automatic press offers unparalleled management of all three parameters, none of which varies without the intervention of the press operator. Changes in any of these three parameters from print stroke to print stroke on a manual press means a potentially costly lesson may be in store once the job moves to an automatic.

Color intensity is another variable that becomes apparent when printing on a manual press. The inconsistencies from manually operating the squeegee, whether producing too light or heavy of a stroke, alter the thickness of the ink film on the garment and, therefore, the absolute color intensity of the print. Even though the condition of the screen itself also plays a crucial role here, the assumption here is that the screen conditions in your shop are the same on both manual and automatic machines. The next installment of this column will take a closer look at the screen’s influence.

Squeegee and screen variables, and their negative effects on print quality and consistency, are only magnified when we start talking about process-color printing. For example, any variation in the squeegee stroke in process-color printing will affect dot gain and hurt print intensity, definition, and resolution. Automatic presses are designed to handle accurate halftone reproductions and meet other demands associated with high-end work. Once again, you’ll be better served by printing samples of these premium graphics on the same press—or at least the same kind of press—on which you’ll finish the job run.